We investigate the possibility of the optical computation of the Laplace operator in the oblique incidence geometry using a layered structure consisting of a set of homogeneous thin films. For this, we develop a general description of the diffraction of a three-dimensional linearly polarized optical beam by a layered structure at oblique incidence. Using this description, we derive the transfer function of a multilayer structure consisting of two three-layer metal-dielectric-metal structures and possessing a second-order reflection zero with respect to the tangential component of the wave vector of the incident wave. We show that under a certain condition, this transfer function can coincide up to a constant multiplier with the transfer function of a linear system performing the computation of the Laplace operator. Using rigorous numerical simulations based on the enhanced transmittance matrix approach, we demonstrate that the considered metal-dielectric structure can optically compute the Laplacian of the incident Gaussian beam with the normalized root-mean-square error of the order of 1%. We also show that this structure can be effectively utilized for optical edge detection of the incident signal.
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http://dx.doi.org/10.1364/OE.489750 | DOI Listing |
Sensors (Basel)
December 2024
Directorate for Railways, Nemanjina 6, 11000 Belgrade, Serbia.
The manuscript conducts a comparative analysis to assess the impact of noise on medical images using a proposed threshold value estimation approach. It applies an innovative method for edge detection on images of varying complexity, considering different noise types and concentrations of noise. Five edges are evaluated on images with low, medium, and high detail levels.
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December 2024
LAPLACE Laboratory-UMR5213, National Polytechnic Institute of Toulouse, 31077 Toulouse, France.
This paper introduces a novel methodology for evaluating communication performance in rotating electric machines using Received Signal Strength Indication (RSSI) measurements coupled with artificial intelligence. The proposed approach focuses on assessing the quality of wireless signals in the complex, dynamic environment inside these machines, where factors like reflections, metallic surfaces, and rotational movements can significantly impact communication. RSSI is used as a key parameter to monitor real-time signal behavior, enabling a detailed analysis of communication reliability.
View Article and Find Full Text PDFSci Rep
January 2025
Oeschger Centre for Climate Change Research (OCCR), University of Bern, Bern, Switzerland.
The impacts of climate change on human health are often underestimated or perceived to be in a distant future. Here, we present the projected impacts of climate change in the context of COVID-19, a recent human health catastrophe. We compared projected heat mortality with COVID-19 deaths in 38 cities worldwide and found that in half of these cities, heat-related deaths could exceed annual COVID-19 deaths in less than ten years (at + 3.
View Article and Find Full Text PDFAdv Mater
January 2025
National Key Laboratory of Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China.
As one of the typical applications of metamaterials, the invisibility cloak has raised vast research interests. After many years' research efforts, the invisibility cloak has extended its applicability from optics and acoustics to electrostatics and thermal diffusion. One scientific challenge that has significantly restricted the practical application of the invisibility cloak is the strong background dependence, that is, all passive cloaking devices realized thus far are unable to resist variation in the background refractive index.
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December 2024
Department of Mathematics, Ghazni University, Ghazni, Afghanistan.
The current manuscript presents a mathematical model of dengue fever transmission with an asymptomatic compartment to capture infection dynamics in the presence of uncertainty. The model is fuzzified using triangular fuzzy numbers (TFNs) approach. The obtained fuzzy-fractional dengue model is then solved and analyzed through fuzzy extension of modified residual power series algorithm, which utilizes residual power series along with Laplace transform.
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